Chronic interstitial nephritis, analgesics and NSAIDs nephropathies

1. Big picture

Chronic interstitial nephritis, also called chronic tubulointerstitial nephritis, is a slowly progressive kidney disease where the main damage is in the tubules and interstitium, not primarily in the glomeruli.

The key exam pattern is:

Long-term analgesic/nonsteroidal anti-inflammatory drug use → chronic tubulointerstitial damage → impaired concentrating ability, nocturia/polyuria, sterile pyuria, mild proteinuria, hematuria, papillary necrosis, progressive chronic kidney disease.

Analgesic nephropathy is especially important because it is preventable: stop the offending drug early and progression may slow or even be prevented in mild disease.